Geochemistry

Methods and collections

Investigating the chemical information in fossils

A fossil’s shape is not its only source of information. Its chemical composition can preserve evidence of environments and changes that occurred during fossilisation.

Chemical preparation of samples in the laboratory. — Phosphate separation before isotope analysis. Photo: © Jean Goedert. Dinosaures, les géants du vignoble, 2017, p. 109.

The method in practice

The work begins by selecting samples and the elements to analyse. Laboratory preparation precedes measurement. Analyses distinguish preserved chemical signatures from changes caused by fossilisation. Interpretation draws on geology, anatomy and other contextual data.

At Angeac and in regional comparisons

Oxygen isotopes preserved in phosphates can reveal relationships between animals and aquatic environments. At Cherves-de-Cognac and Angeac, analyses use separate sample series. Comparisons account for chemical preservation and the ecology of the organisms.

What this research reveals

At both Cherves and Angeac, chemical analyses complement the study of fossils and sediments to reconstruct ancient environments.

2026 · Published research

How do droppings become fossils?

Elemental mapping of 50 coprolites distinguishes biological signals from changes caused by fossilisation. Chemical composition does not simply reflect the last meal.

View the publication →

People and expertise

Jean Goedert, involved in the Angeac project since its beginnings, combines isotope geochemistry and vertebrate palaeontology. He contributes in particular to studies of coprolites and turiasaur teeth.

Jean Goedert contributes to the geochemistry of fossils and environments. Field and laboratory expertise are combined to check sample provenance and preservation.

Jean Goedert

All the people behind the project →